<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>111</title>
		<style type="text/css">
			body{
				font-size: 4px;
			}

			.box1{
				width: 100px;
				height: 100px;
				background-color: #3CFF7A;
				position: relative;/* 开启相对定位 */
			}
			.box11{
				width: 50px;
				height: 50px;
				background-color: #eb0d36;
				position: absolute;/* 开启绝对定位 */
				margin: auto;
				left: 0;
				right: 0;
				top: 0;
				bottom: 0;
			}
			.box2{
				width: 100px;
				height: 100px;
				background-color: #4e9bff;
				position: relative;/* 开启元素的相对定位 */
				left: 100px;
				top: -100px;
			}
			.box3{
				width: 100px;
				height: 100px;
				background-color: #ff8040;
				position: absolute;/* 开启绝对定位 */
				top: 0;
				left: 200px;
			}
		</style>
	</head>
	<body>
		<div class="box1">1	<div class="box11">
			
		</div>		
		</div>
		<div class="box2">	2		
		</div>
		<div class="box3">	3		
		</div>
	</body>
</html>
